body{
    margin: 0;
    padding: 0;
}
/*<!-----------------------------------头部-------------------------------------->*/
.nav{
    width: 100%;
    height: 58px;
}
.nav .nav-left{
    width: 15%;
    height: 58px;
    background-image: url("../images/3.png");
    background-repeat: no-repeat;
    float: left;
}
.nav .nav-medium{
    width: 65%;
    height:100%;
    float: left;
}

.nav .nav-medium ul{
    margin-top: 0;
    font-size: 20px;
    height: 100%;
    list-style: none;/*去除小黑点*/

}
.nav .nav-medium ul li{
    width: 20%;
    height: 100%;
    float: left;
    width: 20%;
}
.nav .nav-medium ul li a{
    display: inline-block;
    top: 10px;
    width: 100%;
    height: 100%;
    text-decoration: none;
    color: gray;
    line-height: 58px;
    text-align: center;
}

.nav .nav-medium ul li a:hover{
    color: orange;
}
.nav .nav-medium ul li a.first-item{
    color: white;
}
.nav .nav-medium ul li a.first-item:hover{
    background-color: orange;
    color: white;
}
.nav .nav-medium ul li:hover{
    border-bottom: 3px solid orange;
}
.nav .nav-right{
    width: 20%;
    height: 100%;
    background-image: url("../images/5.png");
    float: left;
    background-repeat: no-repeat;
    margin: 0;
}

/*<!------------------------------------横幅----------------------------------------->*/
.banner{
    width: 100%;
    height: 322px;
    margin-top: 3px;
    background-image:url("../images/5.png");
    /*background-color: lightskyblue;*/

    /*letter-spacing: 3px;  设置字符间距*/
    /*word-spacing: 10px;  设置单词间距*/
    /*overflow: scroll;  设置溢出*/
}

.ba-img{
    width: 100%;
    height: 422px;
}

.main{
    width: 80%;
    height: 500px;
    background-color: springgreen;
    margin: 0 auto;
}

/*<!-------------------------------------底部----------------------------------------------->*/
.footer{
    width: 100%;
    height: 100px;
    background-color: cadetblue;
}